The present invention relates to a spectacles frame holder of the type comprising two jaws, at least one of which is slidably mounted so that the jaws are relatively movable toward or away from each other, and holding means for holding the frame between the jaws in a reference plane.
The routing or shaping of the contour of optical glass or lenses to the shape of a spectacles frame requires that the shape of the frame be precisely entered in a computer memory. This operation is carried out by using an apparatus which is capable of following and analyzing the frame rims.
To ensure precise contact, it is essential to correctly hold the frame in a stationary position during the analysis of the frame. For this purpose, a frame holder of the aforementioned type has been used. The holding means may be formed by frame-clamping clamps which are movable in a direction perpendicular to a reference plane, or by V-shaped centering elements fixed to the jaws.
As the two jaws approach each other, the operator, in some cases, must hold the frame manually until it is taken hold of by the holding means. In more sophisticated equipment, such as that described in FR-A-2 720 524, retractable support rods for the frame rims are provided to facilitate the operation and possibly render it automatic.
In any case, it is necessary to apply the frame against one of the jaws to guarantee that it is "straightened", i.e. not in an oblique position in the reference plane during the analyzing operation, and to avoid deforming the frame by the clamping thereof between the two jaws, even when the frame is easily deformable in its plane, as is the case with many frame models which have very thin metal rims.
The known frame holders do not meet this latter condition in a reliable manner, and thus an object of the present invention is to satisfy this need.